Assays are commonly used for detecting target molecules in a sample for research or diagnostic purposes.
U.S. Pat. No. 7,927,561 discloses methods of detecting an analyte in a fluid sample. The fluid sample is incubated with magnetic particles coated with binding molecules directed to the analyte. The method is based on concentrating the magnetically labeled analyte to a detection region using a focusing magnet.
WO 2011/045436 discloses a lateral flow assay device and a method of detecting an analyte in a liquid sample. The lateral flow assay device comprises a sample zone and a reaction zone forming a flow path for the sample. The method employs a first capture molecule which carries a non-magnetic label and a second capture molecule which carries a magnetic particle.
WO 2011/030286 discloses a method for detection of an analyte in a sample comprising a plurality of capture moieties capable of binding to said analyte. At least one of the capture moieties is bound to a solid substrate and at least one other capture moiety is bound to a detectable marker, wherein the detectable marker is a large particle marker having a particle size of ≥50 nm-≤5,000 nm. This assay is performed as a “sandwich assay” in which the analyte is caught between two different capture molecules.
Many detection assays involve immobilization of target molecules onto a porous substrate (e.g. a membrane) followed by incubation with target binding agents (e.g. Dot blot or Western blot). The target binding agents are labeled (either directly or via a secondary binding agent) such that upon performing a suitable reaction, a signal is formed indicating the presence of the target molecule and its amount.
The Western blotting workflow is long, arduous and often takes more than a day from start to finish. After protein transfer to the blotting membrane there is a development process that takes from 3-4 hours to overnight to complete. The development process includes membrane blocking, antibody probing, repetitive membrane washing and signal detection; this is the most tedious portion of the entire workflow.
Therefore there is a need for developing an assay that improves the speed of substrate-based detection methods.